This invention relates to finish compositions for synthetic yarns.
Recently, conditions which are required for the production and fabrication of synthetic yarns are becoming increasingly severe and higher processabilities are coming to be required of the finishes which are used in their production and fabrication. In the case of synthetic filaments used for textured yarns, sewing threads, tire cord yarns and also as materials in various industries, particularly severer production and fabrication conditions are being adopted. For textured yarns of polyester, nylon and acryl, for example, heater temperature is set to 200.degree.-240.degree. C. for yarns traveling at a fast rate of 400-1200 m/min and a continuous operation extending over several weeks is required under such conditions. For tire cord yarns, heater temperature is set to 200.degree.-250.degree. C. for yarns which are drawn with a high tensile force and the absence of fluffs and filament breakage is required under such conditions. Similar requirements are also imposed on filaments for sewing threads and those used as various industrial materials.
If there is fuming from a finish composition used in the production or fabrication process of synthetic yarns, on the other hand, the work environment is adversely affected and the apparatus as well as the yarns become contaminated by the generated mist of oil. If the finish composition becomes colored when it is heated, this has the effect of degrading the yarn quality. If tar is generated from these finish compositions, heat efficiency becomes low and fluffs and filament breakages occur because the running of the yarn is obstructed. If the lubricity of the finish composition is not sufficient, furthermore, abrasion of the components contacting the running yarns is accelerated and the damage to the yarns also becomes more serious. If the finish composition is poor in boundary friction lubricity, fluffs and filament breakages occur frequency under high tensile conditions.
Although many compounds have been considered as a finish composition for synthetic yarns, none of them simultaneously possesses the heat resistance and dynamic and boundary friction lubricity satisfying the recent requirements as described above. For example, aliphatic esters of polyhydric alcohol (such as trimethylol propane) having a neo structure within the molecule (as disclosed in Japanese Patent Publication Tokko No. 44-29552) have higher dynamic friction and poor boundary and hence are not sufficient in dynamic and boundary friction lubricity under high-speed and high-tensile conditions. Fatty esters of ethoxylated bisphenol-A (as disclosed in Japanese Patent Publication Tokko No. 47-29474) are poor in dynamic friction lubricity and have the problems of fluffs and yarn breakages. Esters derived from thiodicarboxylic acid (as disclosed in Japanese Patent Publication Tokkai No. 52-103590) are poor in boundary and have the problem of inferior boundary friction lubricity. Compounds derived from thiodicarboxylic acid and neopentyl glycol (as disclosed in Japanese Patent Publication Tokkai No. 52-103593) have the problem of being poor in both dynamic and boundary friction lubricity. Esters of an alkyl or alkenyl thiocarboxylic acid and a polyhydric alcohol such as neopentyl glycol (as disclosed in Japanese Patent Publication Tokkai No. 57-82573) have superior heat resistance but since they have a poor boundary, they have the problems of fluffs and yarn breakages under high tensile conditions and of being poor in boundary friction lubricity. Diesters of esterdiol obtainable from one mole of a glycol having quaternary carbon such as neopentyl glycol and one mole of a hydroxy carboxylic acid similarly having quaternary carbon such as hydroxypivalic acid and aliphatic monocarboxylic acid (as disclosed in Japanese Patent publication Tokkai No. 50-136499 and British Patent No. 1492052) are superior in dynamic friction lubricity under high-speed running conditions and boundary friction lubricity under high-tensile conditions but have the problems of coloring and tar deposits when heated and also of being poor in heat resistance.